For a semi we normally recommend Stormy Mondays as with a semi guitar you tend to get a bigger sound anyway.
As Ratrod explained even Slash uses low output pickups with Alnico IIs which is what the Stormy Monday is, DCing around 7.7 on the bridge and 7.1 on the neck with Alnico II magnets. In my opinion i would not go much hotter then that maybe a Mule or something around that area if you think you will need more off the bridge.